Abstract: The Yongxin gold deposit is a large, fracture-controlled ore deposit in  the Duobaoshan gold-copper metallogenic belt within the eastern domain of the  Central Asian Orogenic Belt (CAOB). Silicification, sericitization and potassic  alteration are the main hydrothermal alteration types which display successive  zoning surrounding the ore-bodies. Pyrite, galena, sphalerite and chalcopyrite are  the major metallic minerals in the deposit, and gold is mainly distributed in pyrite.  Here we investigate the trace element composition and isotope (Pb and S)  characteristics of pyrite from this deposit. The auriferous pyrite is mainly  allotriomorphic and homogeneous in chemistry with a homogenous distribution of  As, Ni, Mo and Fe from the core to rim of grains. These features are consistent with the ²⁰⁷Pb/²⁰⁶Pb-²⁰⁶Pb/²⁰⁴Pb, and ²⁰⁸Pb/²⁰⁴Pb-²⁰⁶Pb/²⁰⁴Pb of the grains that  suggest a single source with no evidence for involvement of late fluids. The δ³⁴S values range from +3.5‰ to +5.4‰ with an average of +4.48‰, suggesting a  mantle-derived magmatic provenance for the sulfur. The high Co content and  Co/Ni ratios, low Ni and Mo/Ni ratios suggest a mafic/ultramafic source for the  Yongxin gold deposit. The Co-Ni-As relation indicates a magmatic hydrothermal  affinity with a classification as epithermal gold deposit. High arsenic and gold  contents on the rims of pyrite grains indicate that Au and As were simultaneously  precipitated in anoxic, low temperature and near-surface conditions.